How to "unravel" a model?
First I would start by making the initial cuts. This is called "ripping" a mesh - press V in Edit Mode while the edges you want to cut/rip are selected. Then Press Esc to snap them back to their original location (they're still ripped). 

From Object Mode, in the Mesh Context add two Shape Keys, the Basis and one more. After selecting the second Shape Key, Tab back into Edit Mode.

You can then enable Proportional Editing AltO and with the ripped vertices selected pull them to the peeled back position. Sharp Falloff may be the best falloff curve to use when doing this. 

Tab back to Object Mode and move the Shape Key slider to see the peel-back effect animated.

You can then add a Solidify Modifier to generate the thickness of the suit automatically.



This is just a basic answer to get you started, as your question is really pretty large in scope (it's a project of its own). You may need to use cloth simulation. You may need to use a Shrinkwrap Modifier to get the suit to fit precisely onto a body. You may need to even rig parts of the rubber suit. There isn't really one quick method for doing this that I know of, but a combination of the techniques I mentioned above can probably be used to achieve a satisfactory result. Good luck!